'.\" t
.TH "dusp" "1M" "Jun 27, 2006" "1\&.2\&.0"
.SH NAME
dusp \- Perform instant software reset

.SH SYNOPSIS
.TS
l l.
dusp 	Reboot the server instantly
.TE

.SH DESCRIPTION
\fBBeware that this utility is dangerous!\fP When run it will instantly
reboot the current machine - \fBwithout even syncing any depending
cached data to disk!\fP.

This function is intentionally designed to reset the server as quickly
as possible. It is used by the cluster daemons to ensure that when
certain cluster conditions are detected one or other of the servers
will reset instantly.

Although it may seem counter-intuitive, use of this utility aims to
protect data - not corrupt it.

.SH CLUSTER CONDITIONS USING 'dusp'
Obviously reseting a server in this manner could result in data corruption,
and hence the conditions for when such an action occurs must be fully
understood.

.SS Explicit Request by Cluster Administrator
When the cluster daemon on one node wishes to perform a reset of the
other node it does so via the following message sent to the cluster
daemon:

.TS
l.
TOC
.TE

If desired the system administrator could send this message to the local
or remote cluster daemon via the \fBcldaemonctl(1M)\fP utility if they
so desired.

.SS Inconsistent Application Status
If a node joins (or rejoins the cluster after a network outage), both
nodes compare the state they believe exists amongst the registered
applications. If both nodes believe they are each running a particular 
application then the one that has been running the application the longest
is sent the 'TOC' message.

The purpose of this request is to ensure that if at all possible 
the application only appears at a single IP/Machine Address thus removing the 
chance of data being updated individually on both systems.

.SS Loss of Cldaemon connection but Host Connectivity Remains
If it appears that the remote daemon dies on the secondary 
node the primary will check on a regular basis to ensure 
the cluster daemon does not re-appear with a different configuration.

.SH EXIT STATUS
It doesn't - the machine is reset immediately.

.SH SEE ALSO
.TS
l l.
cldeamon(1M)	- Cluster status Daemon
cldeamonctl(1M)	- Cluster Daemon Control utility
.TE

.SH AUTHOR
The \fIdusp(1M)\fP utility was written by Simon Edwards, 2004-2006. The
author can be contacted via the website mentioned below.

.SH AVAILABILITY
This software is freely available from the Linuxha.net website - please see
\fBhttp://linuxha.net\fP for more details.

.SH WARRANTY
This is Open Source Software is per the GNU GPL. It is free to use and
distribute but \fIcomes with no warranty whatsoever\fP. For more information
on the license please see \fBwww.gnu.org/copyleft/gpl.html\fP.

